Cylinder injection type internal combustion engine, control method for internal combustion engine, and fuel injection valve

Abstract

There is provided a cylinder injection type internal combustion engine capable of performing stratified charge operation at the time of a vehicle speed of 120 km/h and/or an engine rotational speed of 3200 rpm to enhance the fuel efficiency and/or to observe the emission regulations. In the internal combustion engine, a stratum of air and/or air flow is formed between a fuel spray injected from an injection valve and the top face of a piston and/or the wall surface of a combustion chamber, and a face shape contrived to guide the air flow is formed on the top face of the piston.Also, the stratified charge operation can be performed even at the time of cold start or cranking.

What is claimed is:  
     
       1. A cylinder injection type internal combustion engine, comprising: 
       a combustion chamber into which air is sucked;  
       a fuel injection valve for injecting fuel directly into said combustion chamber;  
       an ignition plug for igniting the injected fuel  
       a piston for changing the volume of said combustion chamber,  
       wherein said piston has a top face configured to allow the flow of air to go from the side of the wall surface in said combustion chamber opposite to said fuel injection valve to just under said fuel injection valve, and  
       air layers are formed between the piston and an injected fuel spray, one of the air layers flowing on the face of the piston and another of the air layers flowing in opposite directions such that fuel spray is isolated from the top face of said piston and diffusion of the fuel spray throughout the combustion chamber is minimized so as to concentrate the fuel spray in a region of the ignition plug.